Regulating combustion in furnaces



F. H. BROWN.

REGULATING COMBUSTION IN FURNACES.

APPLICATION FILED FEB; 12, I920.

Patented May 4, 1920.

2 SHEET$$HEET I- jive/6&7."

"km N F. H. BROWN. REGULATING COMBUSTlON IN FURNACES.

APPLICATION FILED FEB-12, I920.

Patented May 4, 1920.

2 SHEETS-SHEET 2.

I h nn UNITED STATES PATENT OFFICE.

FRANCIS H. BROWN, 01? PHILADELPHIA, PENNSYLVANIA, ASSIGNOR 'TO JOHN M. HOPWOOD, 0F PITTSBURGH, PENNSYLVANIA.

REGULATING- COMBUSTION IN FURNACES.

Specification of Letters Patent.

Patented May 4;, 1920.

Substitute for application Serial No. 184,260, filed August 3, 1917. This application filed February 12, 1920. Serial No. 358,107.

natural and reduced draft conditions, 7 by' and'in accordance with the flow of steam from the boiler. The invention is hereinafter more fully described and claimed.

In the accompanying drawings forming a part of this specification, Figure 1 is a diagrammatic view showing a boiler and its setting and connections having applied thereto apparatus and mechanical devices suitable for the practice of the invention, claimed herein; Fig. 2 is a sectional view on an enlarged scale of a form of differential mechanism operated by differences between the static pressure and the total pressure of steam flowin from the boiler; Fig. 3 is a detail view of a portion of the compensating mechanism shown in Fig. 2; Fig. 4 is a sectional view of a pressure actuating device for controlling the feed of fuel; Fig. 5 is a detail view illustrating a modification of the improvement.

The invention claimed herein may be practised in connection with any suitable form, type or construction of furnace or fire box for boilers or other purposes, and any suitable type or construction of stoking mechanism may be employed for feeding" fuel into the furnace. In the construction shown, what is known as a traveling or chain grate 1 is employed for feeding fuel into the fire box 2 of a boiler 3, which is provided as shown with an outlet pipe 4, leading to an engine or other point of utilization of the steam.

In the practice of the invention, suitable the nozzles 7 and 8 extending from the respective passages in said tube, are connected by pipes 9 and 10 to a pressure-operated motor, such for example as the diaphragm motor shown in Fig. 2. As shown therein, the pipes 9 and 10 are connected to a shell 11 on opposite sides of a diaphragm 12 of suitable design, arranged across the shell. This diaphragm is adjustably connected by an arm 13 and a turn buckle 14 to a pivot-.

ally mounted frame 15. On the frame is pivotally mounted a bell crank lever 16 having one end connected by a rod 17 to a movable member of a suitable valve mechanism 18. The opposite end of the bell crank is connected by a rod 19 to a pin 20 on the pivotally mounted'standard 21 as indicated in Figs. 2 and A shoe 22 is pivotall mounted on the upper portion of the stand ard 21 and is adapted to be engaged by and permit of the movement of an angularly arranged rod 23 which is so mounted on a frame 24 as to permit of its angular adjustment. The frame 24 is secured to a rod 25, having its upper end connected by an arm 26 to the piston rod 27 of a fluid pressure cylinder 28. In the operation of this mechanism, the movement of the diaphragm 12 will shift the movable member of the valve mechanism 18 to admit'of the flow of fluid under pressure from the supply pipe 29 to and through one or the other of the pipes 30 or 31, connected respectively to the upper and the lower ends of the cylinder 28, thereby causing a movement of the piston 32 in said cylinder. As the piston moves, the angularly arranged rod 23 will also be shifted and by means of its angular position will rock the standard 21 and by reason of the engagement of the standard with the bell crank lever 16, will shift the movable member of the valve mechanism 18 in a direction opposite to that imparted by the shifting of the frame 15 by the diaphragm, thereby cutting off any further flow of fluid under pressure to the cylinder 28 and stopping further movement of the piston 32.

to the damper consists of a flexible cable 36 passing around guide pulleys 37 and in a suitable manner operatively connected to a within the fire chamber 2 controlled by the damper 34 in the conduit. When no steam is being employed or flowing from the boiler, there will be no difference of pressure to effect a change in the position of the movable member of the diaphragm and parts operated or controlled, but as soon as steam begins to flow, pressure will increase on top of the diaphragm and the downward movement of the-diaphragm will cause such a shifting of the valve mechanism 18 as to admit fluid under pressure to the piston 32 and thereby open the damper 31 in the conduit, thus permitting such an outflow of gases as will reduce the pressure of the fire chamber 2. This reduction of pressure will cause the operation of the pressure actuated device A connected as shown to the fire chamber 2, to adjust the stoking mechanism so as to increase the fuel supply. The opening of the damper 3&1 will also permit of the flow of an increased quantity of air through the fuel, such increased flow of air being proportional to the additional quantity of fuel beingfed. In case the increase in combustion causes the generation of greater quantities of gas than can escape past the damper in its adjusted position, there will be an increase of pressure in the fire box and such pressure operating on the mechanism A will reduce the rate of feed of fuel. This automatic adjustment will continue until the rate of generation of gas is substantially equal to the discharge capacity of this conduit with the damper in its adjusted position. The feed of fuel to the fire chamber and the correct supply of air for the combustion of the fuel, will be proportional to the flow of steam through the pipe 4. In case of a greater demand for steam and an increased rate of flow through the steam pipe, the damper will be further opened, again decreasing the pressure in the fire chamber. such decrease of pressure serving to operate the pressure actuated device to increase the feed of fuel. The opening of the damper whereby the feed of fuel is increased, also permits increased but suitably graduated and controlled volumes of air to flow through the fire chamber and increase combustion.

Any suitable form or construction of pressure actuated device may be employed for controlling the feed of fuel, such for example as that shown in Fig. 1 of Patent No. 1,150,097, granted August 17, 1915, to F. H. Brown, and also shown in Fig. 1 in this application. This pressure actuated device consists of a conduit 39 in communication with a combustion chamber 2 and extending above the liquid in a tank -10. The conduit discharges into an inverted vessel 41, the lower edge of such vessel being immersed in the liquid in the tank. This vessel is connected by a lever 42, preferably counterbalanced as shown to a valve mechanism 43. controlling the admission and discharge of motive fluid through the pipes 44 and 45, connected to opposite ends ofthe cylinder 46. The rod 17 of the piston in said cylinder is connected to a bell crank lever 45, while the opposite end of such lever is connected preferabl 1 by a pitman 19 to a swinging arm 50. Tie upper end of this arm is connected to or forms a part of the strap surrounding the eccentric 51 on the shaft 52 driven through a belt by a motor 53 or by any suitable means. The lower end of this swinging arm 50 is connected to a block 54:, movably mounted in a slot formed in a lever 55, said lever being provided with a pawl 56 adapted to engage a ratchet wheel. 57 on one of the shafts forming part of the driving mechanism of the chain grate 1. It will be readily understood that the rotation of the eccentric will effect an up and down movement of the swingingarm and that the amplitude of the movement of the lever carrying the pawl will be dependent upon the position of the block 54 along such lever. The position of this block is controlled by the pressure actuated device hereinbefore described, through the pitman 49, as stated.

If necessary or desirable, the normal ull or draft of the stack may be increased by any means known in the art, such for example'as a blower as shown in Fig. 5. While such augmented draft can be controlled by a suitably arranged damper as hereinbefore described, the operation of the blower can be controlled, a convenient construction to that end consisting in employing an electric motor 58 for operating the blower 59 and controlling the operation of the motor by a rheostat, the movable element of the latter being connected to the piston of the cylinder 28 of the primary controlling mechanism, so that the position of the movable member of the rheostat will bear a definite relation to the flow of steam through the pipe 4.

When a battery of boilers are employed, each boiler will be controlled in the manner hereinbefore described, and hence the uniform rate of combustion will be maintained irrespective of the thickness of the bed of fuel in the furnaces of the different boilers.

The same rate of combustion will be maintained on both thick and thin fires, and the rate of combustion in each furnace will be automatically varied in accordance with the rate of flow ofsteam from its own boilers.

This case is filed in place-of application Serial Number 184260 filed August 3rd,

1917, but became abandoned February 21,

I claim herein as my invention:

1. The method herein described of controlling combustion in furnaces of boilers, which consists in varying the pressure in furnaces by and in accordance with the flow of steam from the boiler and regulating the feed of fuel tothe furnace by and in accordance with the variations of pressurein the furnace.

2. The method herein described of controlling combustion in furnaces of boilers which consists in regulating the flow of gases from the furnace by and in accord ance with the flow of steam from the boiler and regulating the feed of fuel to the furnace by andin accordance with the changes in pressure in the furnace.

3. The method herein described of 'controlling combustion in furnaces which consists in varying the induced draft from the m hand.

y FRANCIS H. BROWN. 

